Gallstones (cholelithiasis) tend to form when the bile concentrations of bile acids, cholesterol and lecithin are altered. This results in a loss of aqueous solubility with precipitation as crystals. Certain conditions are associated with certain types of stones and with the frequency of their occurrence. While many of the risk factors cannot be modified, some factors such as diet or medication can be changed to lower the total risk.


Gallstone types:

(1) pure cholesterol

(2) pigment

(3) mixed


Factors Increasing Gallstone Formation

(1) Demographics (combination of genetic, diet and cultural factors)

(1a) Northern Europe, North America and South America: favor cholesterol and mixed stones

(1b) Asia: favor pigment stones

(1c) Native American women

(1d) Hispanic women

(2) increasing age (usually after the age of 40)

(3) female gender (estrogens)

(4) pregnancy

(5) obesity (> 30% over ideal body weight)

(6) rapid weight loss and/or fasting (risk can be reduced with ursodeoxycholic acid therapy)

(7) high calorie, high fat diet

(8) total parenteral nutrition for prolonged periods

(9) chronic hemolysis (favor pigment stones)

(10) ileal disease or resection

(11) alcoholic cirrhosis

(12) chronic biliary tract infection

(13) chronic biliary parasitic infestation

(14) drug therapy

(14a) clofibrate

(14b) octreotide

(14c) oral contraceptives


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